In recent years, agriculture and animal husbandry production in the western Sichuan plateau was greatly affected by drought, therefore, it was necessary to study the applicability of remote sensing drought comprehensive index in the grassland area of the western Sichuan plateau. In this study, the vegetation condition index (VCI), the temperature condition index (TCI) and precipitation condition index (PCI) were selected to construct the scaled drought condition index (SDCI), which was suitable for the combination of the regional weight of grassland in the western Sichuan plateau, the index monitoring results were verified by standardized precipitation evapotranspiration index (SPEI) during the same period, the characteristics of summer drought from June to August during 2000-2018 were analyzed after the suitable drought grades in the study area were divided. The results show that: (1) The drought judgment index SDCI highlighted the cumulative effect of precipitation and had high monitoring accuracy. It was basically consistent with the monitoring results of SPEI on the drought events in 2006. Only in some places, the scope and intensity of the drought were slightly different from the actual situation. (2) The location of the month-scale drought was mostly distributed in the west and south of Ganzi Prefecture and the south of Aba Prefecture, and in the northeast of Zoige there was mostly no drought in summer during 2000-2018. The degree of drought was stronger in June and August, it was mainly mild to moderate drought, and in July there was mostly mild drought and no drought. (3) The frequency of drought was high and the range was wide in June and August during 2000-2018. In July, the frequency of mild drought was 60.66% in the whole region, and the frequency of drought above mild level was higher (more than 40%) in the southwest, northwest, north and east of Ganzi Prefecture, while the drought frequency in northern Aba Prefecture was lower (less than 40%). The research showed that the SDCI with prominent precipitation effect had the ability to respond to extreme drought events, it could objectively and effectively monitor the drought status of grassland in the western Sichuan plateau.